Filling machine



A. R. THOMPSON 2,285,627

FILLING MACHINE Filed April 32, 1939 June 9, 1942.

4 Sheets-Sheet 1 INVENTOR. A/crf. if. Thom 0am.

ATTORNEY.

June 9, 1942. A. R.- THOMPSON FILLING MACHINE Filed April 22 1959' 4 Sheets-Sheet 2 r INVENTOR. Awe/2f /i. Thar/7,0500.

@M J- a @w ATTORNEY June 9, 1942. A. R. THOMPSQN FILLING MACHINE Filed April '22, "1959 4 Sheets-Sheet 3 INVENTOR. 4&6/1. fi. Thar/7,0800.

A TTORNEYS.

June 9, 1942. A. R. THOMPSON FILLING MACHINE Filed April 22, 1959 4 Sheets-Sheet 4 INVENTOR A/a/f. fi. Tfiompaon ATTORNEY.

Patented J une 9, 1942 FILLING MACHINE Albert R. Thompson, Los Gatos, Calih, asslgnor to Food Machinery Corporation, San Jose,- Calif., a corporation of Delaware Application April 22, 1939, Serial No. 269,362

22 Claims.

, known vacuum filling machines has been occasioned by the fact that such machines have required a high vacuum (usually in the order of at least 27" of mercury), and to maintain efficient operation with this degree of vacuum, an expensive construction is necesary as well as frequent servicing, to maintain all seals eflfective and to maintain the vacuum pump at a high eificiency. In addition, with the. high vacuums used in known machines the external air pres.- sure is sufiicient to frequently cause collapse of the walls of the cans ordinarilyused so that it has been necessary to provide bracing means for supporting the walls of the cans during the filling operation.

The filling machine of the instant invention is designed to eliminate \the foregoing disadvantageous features and to provide a filling machine of inexpensive construction, which operates with a relatively low vacuum so as to need no special supports or can bracing means, and which obtains a high degree of accuracy in maintaining the desired constant head space in the can, irrespective of whether the filling machine is being used for syruping or for filling operations. A

It is a general object of the invention, therefore, to provide an improved filling machine of the vacuum operated type.

Another object of the invention is to provide a vacuum type filling machine which operates I with a relatively low vacuum and has desirable operating characteristics in maintaining a constant head space in the cans and in providing for clean filling ,of the cans withisubstantially no after-drip. I

A further object of the'invention is provide an improved vacuum type filling machine which can be used withoutadjustment for either syruping or filling operations.

Another object of the invention is to provide a vacuum type filling machine which will operate with a relatively low vacuum.

Another object of the invention is to provide a filling machine of the character referred to, which can be adapted readily for use with cans of varying sizes.

Another object of the invention is to provide an improved method of filling cans by vacuum to provide a constant head space in the can irrespective of the amount of solids in the can.

Another objectis to provide for measuring of the free space in a can prior to filling to determine the amount of syrup to be supplied.

Other objects of the invention will appear from the following description of a preferred embodiment thereof, as illustrated in the accompanying drawings, in which:

Fig. 1 is a vertical sectional view through the central axis of a rotary type filling machine with certain parts of the machine shown in elevation.

Fig. 2 is a fragmentary plan view, partially in section, of the filling machine shown in Fig. 1.

Fig. 3 is a fragmentary sectional view taken in the plane of the line 3-3 in Fig. 2.

Fig. 4 is an enlarged vertical section through one of the filling valves similar to that shown at the right of Fig. 1.

Fig. 5 is a plan view of the filling valve of Fig. 4 with the dome of the equalizing chamber removed.

6 is a plan view of the valve seat of the filling valve. I

Fig. 7 is a vertical sectional view through the valve seat taken in the plane of the line 1-1 in Fig. 6.

Figs. 8 through 15 are diagrammatic views illustrating the operation of the valve during a.

filling operation.

Figs. 8 and 9 are respective diagrammatic sectional and plan vie'wsshowing the position of the parts during the first vacuumizing step of the filling operation.

Figs. 10 and 11 are similar view showing the position otthe parts during the first pressure equalizing step of the filling operation.

Figs. 12 and 13 are similar views showing the positionof the parts during the second vacuumizing step of the filling operation.

Figs- 14 and 15 are similar views showing the parts during the second pressure equalizing step, together with the filling step of the filling operation.

mg. 16 is a sectional view or the ho-can-no fili device taken in a plane indicated by the line |6|6 in Fig. 2.

Generally, my invention contemplates the provision of a source of liquid, a source of vacuum, and one or more filling heads for utilizing the vacuum to fill liquid into cans or other containers which are imported by can lift means in operative relation with the filling heads, which operate to measure the amount of solids, if any, in the can and to proportion the amount of vacuum to be used in drawing liquid into the can and hence to determine the amount of liquid filled into the can.

Each filling head includes an equalizing chamber of predetermined pressure and volume; and valve means for selectively connecting the can engaged with the head to the source of vacuum, then to the equalizing chamber, thereafter tothe source of vacuum, and then simultaneously to the equalizing chamber and to the source of liquid. When the can is first connected to the vacuum source, a vacuum of the selected pressure is drawn on the can. Then, when the can is connected to the equalizing chamber, (at which time it is shut off from both the source of liquid and the source of vacuum) so that an equalizing of the pressures occurs, and the resulting pressure is a function or measure of the amount of free space in the can. This vacuum pressure is then trapped in the equalizing chamber for subsequent use, and the can is again vacuumized. Subsequently, when the can is connected to both the equalizing chamber and the source of liquid, the combined pull of both vacuum pressures is exerted to draw liquid into the can to fill the can to a predetermined level, and because of the measuring of the amount of free space in the can, the can will always be filled very closely to such level.

Referring'to Figs. 1 and 2, the illustrated embodiment of my invention comprises generally a filling tank l5 having a plurality of filling heads I6 mounted about the periphery thereof for cooperation with cans carried by can lift plates l1 suitably mounted for vertical sliding movement on a can lift table l8 which rotates with the tank and the filling heads in the usual manner.

The tank |5 includes a threaded hub 2| for engagement with the upper end of a threaded sleeve 22 suitably journalled on center post 23. The threaded connection between the hub 2| and the sleeve 22 provides for vertical adjustment of the filling tank relative to the can lift table I8 to accommodate different heights of cans in the machine. To clamp the tank in its adjusted position, the upper end of the sleeve 22 is slotted as at 24 and is provided with threaded bosses 25 to receive the reversely threaded ends 26 of an expansion coupling 21, the ends 26 being of different diameter to insure installation of the coupling in the proper manner. It will be noted that by turning the coupling 21 the sleeve 22 can be expanded or contracted as desired to lock the tank in position or to allow adjustment therelevel. For this purpose, a vertically disposed liquid supply pipe 3| (Fig. 1) is secured within a sleeve 32 by means of a clamping nut 33 and sealing washers 34 at the upper end. Both pipe 3| and sleeve 32 have their lower ends secured as by means of a press fit within a. hub 36,

which are of a generally rectangular shape and lead downwardly from the hub 36 and extend beneath the liquid level 38 within the tank. The entire assembly is supported from the sleeve 32. which is clamped by bolts 4| in a central boss 42 of transverse bracket 43 which is suitably mounted on the frame |8 (Fig. 2) of the filling machine by a pair of opposite posts 44, only one of which is shown in each of Figs. 1 and 2. Each end of the bracket 43 (Fig. l) is adjustably connected at 45 to the associated post 44 to provide for vertical adjustment of the assembly in accordance with the vertically adjusted position of the tank.

The means for insuring a constant level of the liquid in tank l5 includes annular float 5| which is guided for vertical movement by rods 52 extending through apertured ears 53 of the pipes 31, the vertical movement in either direction being limited by collars 54 suitably secured on the rods 52 between the ears 53. The upper end of right-hand rod 52 (Figs. 1 and 2) is pivotally connected at 56 to a lever 51 pivoted at 58 on a bracket 59 formed integrally with the pipes 31. It will be noted that upward movement of righthand rod 52 will effect upward movement of lever 51. The left-hand rod 52 is pivotally connected at El to lever 62 pivoted at 63 on the bracket 59.

It will be noted that upward movement of lefthand rod 52 'will effect downward movement of the inner end of lever 62. The respective inner ends of levers 51 and 62 are. connected by pins 64 with the slotted ends of respective arms 66 secured on the opposite ends of a shaft 61 pivoted in the housing 12 and carrying a mercury switch 68 (Fig. 1) Whose Wire connected 69 extends upwardly through tube 1| centrally disposed within which controls the flow of liquid through the pipe It will be noted that the entire assembly can 3|. be vertically adjusted in accordance with the desired liquid level in the tank so that the mercury switch 68 will be horizontal when the liquid is at the desired height in the tank. The mercury switch 68 is enclosed .by the pipes 31 and suitable housing means 12 at the sides of the pipes 31. A screw plug 13 is provided to permit access to the switch.

As previously stated, a plurality of similar heads l6 are mounted about the periphery of the tank, twenty .valves being shown in the embodiment illustrated. The mounting means for the heads includes an annular bracket indicated generally at 8|, which not only supports the heads but also provides conduits between the heads and the tank. and between the heads and the source of vacuum. As seen in Figs. 1 and 2, the annular bracket BI is secured by means of cap screws 82 to a ring 83 which may be integrally secured about the upper edge of the tank. The bracket 8| is preferably formed as a casting which has a series of vertically disposed interconnected annular bosses 84 from each of which an integral conduit 86 leads inwardly over the side wall of the tank to receive a vertically disposed filling pipe 81 (Figs. 2 and 3) extending downwardly into the tank below the level of the liquid therein.- Each conduit has an adjustable plug 00 threaded at the inner end thereof for a'purpose later described. Thepipe 01 and the conduit 00 open into the filling head through the associated boss 04 to provide a liquid filling passage from the tank to the head whose operation and use is described more fully hereinafter. The source of vacuum supply is provided by means of pipe 0i (Fig. 1) leading from a suitable vvacuum pump and opening into the'sleeve 02 'inaui casting I2I has a threaded flange I 20 to receive and downwardly to respective conduits 00 (Figs.

2 and 3) integrally formed in the bracket 0I and opening into the adjacent bosses 04. The common wall of adjacent bosses 84 is apertured at 01 (Figs. 1 and 2) to provide a part of a continuous vacuum conduit which extends through all of the heads in a manner which will appear later in connection with the description of the valve seat. Thus, a source of vacuum is always available at each head. I

Each filling head is similar in construction and may include a stationary valve seat IOI (Fig. 4), a rotatable valve I02, and an auxiliary vacuum chamber I00 of a predetermined volume above the valve. The valve seat IOI is pressed within the cooperating boss 04 of the bracket 0| and has an annular ledge I04 engaging the lower face of the boss. 'The lower face of the valve seat MI is provided with an annular recess in which rubber sealing ring I06 is pressed to provide a frustoconical lower sealing face against which a can may be engaged by a can lift plate. Within the sealing ring I00 the valve seat IN is recessed at I01 to provide clearance for any fruit project- -ing above the top of the can.

The valve and valve seat are provided with a plurality of passages which operate selectively during the vacuumizing, pressure equalizing, and filling steps of the filling operation. The various passages of the valve seat will be described first.

The valve seat is provided with passages for enabling the flow of liquid from the tank, the vacuumizing of a can, and the pressure equalizing between the can and the auxiliary vacuum chamber. Adjacent its inner edge, the valve seat IOI (Figs. 4, 6, and 7) is provided with L- shaped passage I00 communicating with liquid conduit 00, and also with a passage of the valve as later described. Adjacent L-shaped passage I 00 is a vertical passage I00 which may be connected thereto as later described.

In order to complete the continuous vacuum conduit extending through all the valve seats and the bracket 0|. each valve seat I 0| (Figs. 4, 6, and 7) is provided with a transverse passage 0 which communicates'at each end with the respective apertures 01 in the bosses 04, and has a pair of vertical passages III leading to the upper face of the valve seat. Thus a continuous supply of vacuum is provided at each filling one of passages III head to be used in a manner later described. The

valve seat MI is provided with a pair of inclined holes I I2 and H0 (Figs. 6 and 7) extending between the upper. and lower faces thereof which are used in a manner later described as vacuum passages for transmitting the vacuum from the passage III to the can. The valve seat III is also provided with a pair of verticalapertures 7s 'and. its seat on the casting I2I. The auxiliary chamber I00 is provided by dome I20 and casting I2I and its capacity may be changed by using domes of various sizes. With a particular dome I20, the capacity may be varied by means of a removable post I20 which is mounted by a screw I20 in a threaded boss IOI of the casting I2I so that posts of varying size may be installed easily.

To provide for rotative adjustment of the valve on its seat, the casting I2l (Figs. 4 and 5) has a plurality of cam projections I02, I00, I04, and I00 provided to cooperate, in eflecting rotation of the valve, with respective stationary cam pro- Jections I00 to I00,'inclusive (Fig. 2). suitably mounted on frame I0 as will be described hereinafter.

The valve is also provided with a plurality of connecting passages to cooperate selectively with the passages of the valve seat in the operation of the filling head. The connecting passages may include "a recessed passage I 40 (Figs. 4 and 5) in the lower face of base I22 by means of which the passages I00 and I00 in the valve seat may beplaced in communication to provide for passage of liquid from the tank into a can. In other positions, the recessed passage I40 is adapted to' connect passages H2 and H0 successively with in the valveseat, whereby the can is vacuumized twice during one rotation of the valve on its provided, with a pair of vertical passages I41 adapted to register with vertical passages 4 of the. valve seat whereby communication will be established from the can to the auidiiary vacuum chamber in the dome twice during each rotation of the valve.

With the above description of the various parts Q of the valve, it is believed that the invention can be best further explained by describing the operation 0f -the filling-head.

Referring to Fig. 2, the filling heads I0 are carried in a clock-wise direction as indicated by the arrow, and as they are travelling past station A empty cans are fed to the can lift plates II in the usual manner, the lift plates "and the filling heads travelling together in the usual manner so that as the lift plates are raised in the conventional manner, the cans are moved into air tight relation with the filling heads. When the filling heads are at station A, they are conditioned as shown in Fig. 15, that is, passages I I4 in the valve seat are aligned with passages I4'I of the valve so that the chamber I00 within the dome I20 is open to the atmosphere when a can is fed into' a pre- At its lower end, the arm It: carries a guide seat. The valve I2I is also extension I53 (Fig. 2) for engagement with the cans. Thus, if no can is fed into operative relation with a filling head, the cam projection I36 is maintained inactive, and the remaining cam projections I3'|-I39 will also be ineffective as they are positioned in a plane above the path of the valve cam projection I33. However, when a can is fed into operative relation with a filling head, the bellcrank I36-I52 is moved by the can to the-full line position shown in Fig. 16 where the arm I36 lies in the path of valve cam projection I33, which will therefore be actuated thereby.

A filling head I6 in passing from position A to position B will have its valve actuated if a can is moved into operative relation therewith, by the cam I36 which strikes cam projection I33 so that the valve will be rotated from the position shown in Fig. to that shown in Fig. 9. In this position, the recessed passage I46 of the valve connects one of vacuum passages III with the valve seat passage II3 so that the can I48 (Fig. 8), which is now in sealing engagement with the sealing ring I06 is subjected to the vacuum existing in the pipe 95 as shown diagrammatically in Fig. 8. The vacuum utilized is relatively low, that is not above the order of 21" of mercury. The other passages of the valve being closed, the vacuumizing of the free space in the can is the only action that occurs during the time that a valve is travelling from position B to position C where cam I31 becomes eifective on projection I32 to rotate the valve another one-quarter turn, i. e.,' from the position shown in Figs. 8 and 9 to that shown in Figs. 10 and 11. the vertical pairs of passages H4 and I are aligned so that the pressure in the dome, i. e.,

atmospheric pressure, is equalized with the pressure in the vacuumized can. At this time, the resulting pressure affords a measure of the amount of free space in the can, and will be In this position,

and the volume of chamber I03 is utilized to draw liquid up the pipe 61, through the passage I00 and into the can. The total reduction in pressure within the chamber I03 and the free space in and above the can is suflicient to cause the liquid to rise up pipe 81 through passage I03 into passage I46 .in the valve, and to cause enough liquid to fall into the can to fill it to the desired level, the head space remaining in the can usually having a depth in the order of The flow of liquid ceases when the pressure within the chamber I03 and above the liquid in the can plus the pressure of the column of liquid within the pipe 81 above the level of liquid in the tank becomes equal to the atmospheric pressure. Thus, when the flow of liquid stops, a slight vacuum pressure is present in the space above the can. After the flow of liquid stops, the can is withdrawn from the filling head, and as this occurs the slight vacuum pressure within the can causes a slight inrush of air sufficient to prevent any dripping of liquid, while at the same time the liquid in pipe 81 and passage I 08 drops back to the level of liquid in the tank. In this manner a clean separation of a can from a filling head is effected. After the can is lowered by the operation of the associated lift plate, it is removed in a conventional manner from the filling machine.

It will be noted that by applicants method a measure of the amount of free volume (or, conversely the volume of solids) in a can is provided by equalizing the vacuum pressure in the can with a known volume of air at atmospheric higher or lower in" accordance with the .greater or smaller amount of solids in the can.

This condition obtains while the valve is travelling from'position C to position D where cam projection I38'becomes effective on cam projection I35 to again rotate the valve onequarter turn so that it is moved from the position shown in Figs. 10 andll to that shown in I Figs. 12 and 13. In this position the chamber I03 is sealed off and the pressure therein, which is a function of the free space in the can, is retained for subsequent use as a'measure of the amount of liquid to be drawn into the can. Also, in this position of the valve, the recessed passage I46 establishes communication from the second vacuum passage III through the passage II2 to the can to effect a second vacuumizing operation on the free space in the can. This condition obtains while a filling head is travelling from station D to station E where the fourth stationary cam I39 becomes eifective on the projection I34 to rotate the valve one-quarter turn so that the head is changed from the condition shown in Figs. 12 and 13 to that shown in Figs, 14 and 15.

In Figs. 14 and 15, the vertical pressure equalizing apertures H4 and I4! are again aligned so that a second equalization of pressure occurs, and at the same time the recessed passage I46 connects the filling passage I03 from the tank to the passage I09 leading'to the can so that the filling operation starts as a filling head passes station E.

(III

vacuum suction of the volume within the can pressure in the chamber I03, and then trapping theequalized pressure in the chamber. Preferably, the volume of the auxiliary chamber I03 is selected with relation to the vacuum pressure to be used and with relation to the can size to provide a pull on the liquid together with the vacuumized space in the can in proportion to the part of the can to befilled. The free space above the can and below the valve is restricted so that when a can is filled to the desired level, the vacuumizing thereof and the balancing of the partial vacuum therein with the auxiliary chamber as described will only draw liquid up to but not in passage I46 of the valve. Thus. no liquid will be pulled into a can unless the liquid in the can is below the desired level. It has been found that two successive vacuumizing and equalizing operations performed with a vacuum in the order of 21" of mercury and with proper proportioning of the various volumes obtain a high degree of accuracy and provide for filling of the can with a constant head space remaining for any given size of can, irrespective of the amount of solids in the can.

In order to adjust the valve for use with different sizes of cans, difierent sizes of domes I 26 may be employed to obtain the desired volume in the equalizing chamber. -For small differences in volume the size of the post I28 may be varied to change the effective volume of the dome chamber. Screw plug also enables adjustment in the total volume available under vacuum for drawing liquid from the tank into the can so that desired head space can be adjusted accurately.

While I have shown and described a preferred embodiment of the invention, it is to be understood that the invention is capable of both variation and modification. from the form shown, so that its scope is to be limited only by the scope of the claims appended hereto.

' of vacuum to vacuumize said space, then with I claim: ,1. In a filling machine, a filling head, a vacuum. chamber associated with. said head, and means for connecting a can to be filled with a source of vacuum for drawing a partial vacuum on said can including means for closing the can fromsaid vacuum drawing means and balancing the said vacuum between the said can and said chamber, for connecting said source of vacuum to the can to draw a partial vacuum onthe can with the can closed from said chamber to maintain the vacuum therein, and for subsequently opening communication between said can and said chamber and to a syrup supply with the vacuum drawing means closed oiI, whereby a measured amount of syrup is drawn into the can by the combined vacuums in the can and said chamber.

2. In a filling machine, a filling head ,for receiving a can in air-tight relation, a vacuum chamber, a source of vacuum, a source of liquid, and means for connecting a can to be filled with said source of vacuum to draw a partial vacuum of predetermined value on said can, then with the'vacuum chamber for balancing the vacuum pressure in saidv can with the pressure in said chamber, then with said source of vacuum for drawmga partial vacuum of said predetermined value on said can, and then with said chamber and source of liquid for drawing liquid into said can.:

3. In a filling machine, a filling head for receiving a can in air-tight relation, 2. source of liquid, a conduit leading upwardly from said source of liquid to said head, means for draw n a partial vacuum of predetermined value on said can, and means including a chamber for balancing the vacuum pressure in said can with the pressure in said chamber and for simultaneously connecting said conduit with the'can and chamber, the volume and pressure of said chamber being such that after balancing of the pressures in said can and chamber the vacuum in the can and chamber is sufiicient to draw liquid into the can to a predetermined level but insufficient to draw liquid into the can above the predetermined liquid level therein.

4. In a filling machine, a filling head for receiving a can in air-tight relation, a chamber associated therewith, a source of vacuum, a

. source of liquid, means for connecting the can with said source of vacuum to vacuumize the can engaged with said head, for subsequently equalizing the pressure in said vacuumized can with a predetermined volume of air at a predetermined pressure in said chamber, and for connecting said can and said volume to said source of liquid to draw liquid into the can. I

5. In a filling machine, a filling head for receiving a can in air-tight relation, a source of liquid, a chamber of predetermined volume, means for alternately vacuumizing a can enaged with said head and for equalizing the pressure in said vacuumized can with the pressure of said chamber, and means for connecting said can and said chamber to said source of liquid to draw liquid into the can after at least two successive vacuumizing and pressure equalizing operations. a

6. In a filling machine, a filling head for receiving a can in air-tight relation to provide an enclosed can space, a chamber providing 9. reference space of predetermined volume, a source of vacuum, a source of liquid, means for successively connecting said can space with said source said reference space to equalize the pressure in said can space and reference space, and then with said source of liquid while said can space and reference space are in communication with each other.

7. In a filling machine, a filling head for receiving a can in air-tight relation to provide an enclosed can space, a chamber providing a reference space of predetermined volume, a source of vacuum, a source of liquid, conduit means for connecting said head with the source of liquid, means for successively connecting the can space with said source of vacuum to vacuumize said can space, then with said reference space to equalize the vacuum of the can space with the pressure of said reference space, and then with said conduit means while said spaces are in com munication with each other, to draw liquid into said can.

8. In a filling machine, a source of liquid, a source of vacuum, a vacuum operated filling head having a-can engaging seat and passage means for selectively establishing communication from a can engaged with said seat to said sources of liquid and vacuum, an auxiliary chamber asso.-'

ciated with said head for selective communication with a can engaged with said seat, and valve means for controlling said head to connect a can with said source of vacuum and then with said auxiliary chamber for a plurality of successive vacuumizing and pressure equalizing operations, and for subsequently connecting said can with said source of liquid while still in communication with said auxiliary chamber.

9. In a filling machine, a source of liquid, a source of vacuum, a vacuum operated filling head having a can engaging seat and a va1ve,provided with passage means for selectively establishing communication from a can engaged with said seat to said sources of liquid and vacuum, an auxiliary chamber associated with" said head for selective communication with a can engaged with said seat, means for controlling said valve to connect a can with said source of vacuum and then with said auxiliary chamber for a plurality of successive vacuumizing and pressure equalizing operations, and for subsequently connecting said can with said source of liquid while still in 10. In a filling machine, a source of liquid, a v

source of vacuum, a filling head having means to receive a can in air-tight relation therewith,

-a valve mounted for rotation on said head, an

auxiliary chamber associated with said valve and said filling head, said filling head including re-' spective sets of passage means spaced about said head for establishing communication from a can to said sources of vacuum and liquid a d to said chamber, said valve including other passage means for controlling said sets of passages during rotation of said valve on said head,and means for rotating said valve in step by step fashion to successively connect said'source of vacuum to a can, connect said chamber to the can, connect said source of vacuum to the can, and to connect the can to the chamber and the source of liquid. I

11. The method of syruping partially filled cans which comprises drawing a partial vacuum on the can, balancing the vacuum pressure in said can with an associated space, again drawing said partial vacuum on the can while maintaining the balanced vacuum in the space, and then using the combined vacuums of the space and the can to draw a measured amount of syrup into the can.

12. The method of filling cans with liquid which comprises establishing a reference space of predetermined volume and pressure, drawing a partial vacuum of predetermined value on the can, balancing the pressure in said space with the vacuum pressure in said can to provide a measure of the free space in the can, again drawing a partial vacuum of said predetermined value on the can while retaining the balanced pressure in said reference space, and utilizing the combined suction of said reference space at said balanced pressure and said free space at said partial vacuum to draw liquid into the can.

13. The method of filling cans with liquid which comprises vacuumizing the free space in a can, equalizing the pressure in the vacuumized can space with the pressure of a predetermined reference space, again vacuumizing the free space in the can, and utilizing the combined vacuum pressure of the can and the reference space to draw liquid into the can.

14. The method of filling cans with liquid which comprises, balancing the pressure of the free space in the can with a reference space of predetermined volume and pressure by a plurality of successive vacuumizing and pressure equalizing operations and utilizing the combined vacuum of the can and reference space to draw liquid into the can.

15. In a filling machine, a source of liquid, a source of vacuum, a vacuum-operated filling head having a. can-engaging seat and a valve provided with passage means for selectively establishing communication from a can engaged with said seat to said sources of liquid and vacuum, an auxiliary chamber associated with said head for selective communication with a can engaged with said seat, and means for controlling said valve to connect a can with said source of vacuum and then with said auxiliary chamber for a plurality of successive vacuumizing and pressure equalizing operations, and for subsequently connecting said can with said source of liquid while still in communication with said auxiliary chamber.

16. In a filling machine, a filling head, a vacuum chamber associated with said head, and means for connecting a can to be filled with a source of vacuum for drawing a partial vacuum on said can including means for closing the can from said vacuum drawing means and balancing the said vacuum between said can and said chamber, for connecting said source of vacuum to the can to draw a partial vacuum on the can with the can closed from said chamber to maintain the vacuum therein, for subsequently opening communication between said can and chamber with the vacuum drawing means closed off, to balance the vacuum in the can and chamber, and for connecting the can with a source of liquid while the can is in communication with the vacuum chamber, whereby a measured amount of syrup is drawn into the can.

17. In a filling machine, a source of liquid, a source of vacuum, a filling head having a can engaging seat and passage means, an auxiliary vacuum chamber associated with said head, and conduit and valve means associated with the fillfilling head, conduits for connecting the filling head with the auxiliary vacuum chamber and sources of vacuum and liquid, and means for operating said valve means for selectively establishing communication between the can engaged with the seat and said source of vacuum, the can and auxiliary vacuum chamber, and the can, auxiliary vacuum chamber and source or liquid.

19. In a filling machine, a source of vacuum, a source of liquid, a vacuum chamber, a filling head for engagement with a can, including a conduit for admitting liquid to the can, and a control valve associated with the head for connecting said can with the source of vacuum, said chamber and conduit for a plurality of successive vacuumizing and equalizing operations and for drawing the liquid into the can under the combined vacuum pressure of the can and chamber, said source of liquid being located below the discharge opening of said conduit.

20. In a filling machine, a source of vacuum, a source of liquid, a vacuum chamber, a filling head for engagement with a can, and conduit means for connecting the sources of liquid and vacuum and the vacuum chamber with the filling head, the filling head including a control valve for alternatively connecting the can with the source of vacuum and the vacuum chamber for a plurality of successive vacuumizing and pressure equalizing operations and for subsequently connecting the can with the vacuum chamber and source of liquid for admitting liquid into the can under the combined vacuum pressure of the can and chamber.

21. In a filling machine, a source of vacuum, a source of liquid, a vacuum chamber, a filling head for engagement with a can, and conduit means for connecting the sources of liquid and vacuum and the vacuum chamber with the filling head, the filling head including a control valve for alternatively connecting the can with the source of vacuum and the vacuum chamber for a plurality of successive vacuumizing and pressure equalizing operations and for subsequently connecting the can with the vacuum chamber and source of liquid for admitting liquid into the can under the combined vacuum pressure of the can and chamber, said source of liquid being located below the discharge opening of said conduit.

22. The method of filling cans which comprises vacuumizing the free space in the can, balancing the pressure of the vacuumized can space with a reference space of predetermined volume and pressure, revacuumizing said can space, equalizing the pressure of the revacuumized can space with the established vacuum pressure of the reference space, and utilizing the combined vacuum of the can and reference space to draw liquid into the can.

ALBERT R."I'HOMPSON. 

